Electron Ionization Mass Spectrum of Tellurium Hexafluoride

Article abstract of DOI:10.1021/acs.inorgchem.5b00342

The electron ionization mass spectrum of tellurium hexafluoride (TeF₆) is reported for the first time. The starting material was produced by direct fluorination of Te metal or TeO₂ with nitrogen trifluoride. Formation of TeF₆ was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF₅⁺, TeF₄⁺ TeF₃⁺, TeF₂⁺, TeF₁⁺, and Te⁺, Te₂⁺. A trend in increasing abundance was observed for the odd fluoride bearing ions, TeF₁⁺ < TeF₃⁺ < TeF₅⁺, and a decreasing abundance was observed for the even fragment series, Te(F₀)⁺ > TeF₂⁺ > TeF₄⁺ > TeF₆⁺, with the molecular ion TeF₆⁺ not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species, and their relative stabilities explain the trends in the data and the lack of observed signal for TeF₆⁺. (Chemical Equation Presented).

Full text of DOI:10.1021/acs.inorgchem.5b00342

Article
pubs.acs.org/IC
Electron Ionization Mass Spectrum of Tellurium Hexafluoride
Richard A. Clark,*,† Bruce K. McNamara,‡ Charles J. Barinaga,† James M. Peterson,‡ Niranjan Govind,§
Amity Andersen,§ David G. Abrecht,† Jon M. Schwantes,† and Nathan E. Ballou†
†National Security Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United
States
‡Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352,
United States
§Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland,
Washington 99352, United States
S
* Supporting Information
ABSTRACT: The electron ionization mass spectrum of tellurium hexafluoride
(TeF6) is reported for the first time. The starting material was produced by
direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of
TeF6 was confirmed through cryogenic capture of the tellurium fluorination
product and analysis through Raman spectroscopy. The eight natural
abundance isotopes were observed for each of the set of fragment ions:
TeF5 , TeF4 TeF3 , TeF2 , TeF1 , and Te+, Te2 . A trend in increasing
+
+
+
+
+
+
+
+
abundance was observed for the odd fluoride bearing ions, TeF1 < TeF3
<
+
TeF5 , and a decreasing abundance was observed for the even fragment series,
Te(F0)+ > TeF2+ > TeF4+ > TeF6 , with the molecular ion TeF6+ not observed
+
at all. Density functional theory based electronic structure calculations were
used to calculate optimized ground state geometries of these gas phase species,
and their relative stabilities explain the trends in the data and the lack of
+
observed signal for TeF6 .
analyzer (TGA) for analysis. The tandem setup is the first in
1. INTRODUCTION
the evolution of methodologies that would rapidly quantify
isotopic variation in high performance materials that are
typically encapsulated in natural and man-made matrices.
In this study, volatile tellurium hexafluoride (TeF6) was
produced from the fluorination of two forms of tellurium,
tellurium metal and tellurium dioxide (TeO2). Here, we present
the first known electron ionization mass spectrum of gaseous
tellurium hexafluoride.
The element tellurium (Te) has eight naturally occurring
isotopes with mass numbers ranging from 120 to 130.
Tellurium metal has a melting point of 450 °C and a boiling
point of 988 °C, and the dioxide of tellurium melts at 733 °C
and boils at 1245 °C.16 Fluorine gas reacts with the metal and
dioxide to form three primary products with a product ratio
depending on the reaction temperature.17 At reaction temper-
atures above 150 °C, the product is exclusively tellurium
hexafluoride17,18 with melting point −37.6 °C and sublimation
point −38.9 °C. At a reaction temperature of 60 °C and in the
presence of oxygen, bis(pentafluorotelluryl) oxide
(F5TeOTeF5)17−20 is reportedly formed in addition to the
hexafluoride, with the F5TeOTeF5 species having a melting
point at −36.6 °C and boiling point at 59.8 °C.20 At
Fluorination of metals has been used historically as a technique
for isotopic enrichment by gaseous diffusion1−3 and gaseous
centrifugation.2−5 It has also been discussed as a means for
chemical separation and purification,6−8 and more recently for
nuclear forensic endeavors.9−11 Here, the generation of volatile
metal fluorides is accomplished using nitrogen trifluoride
(NF3). NF3 is unreactive and less hazardous than other
fluorinating agents [e.g., fluorine (F2), bromine trifluoride
(BrF3), krypton difluoride (KrF2), and hydrofluoric acid (HF)]
under ambient conditions, and these qualities make it useful for
screening fluorination behavior safely.12−15 However, NF3, like
all fluorinating agents, is an oxidizer and should be handled
with care. Additionally, the low reactivity of NF3 allows for
selective fluorination of different species, which volatize at
specified temperatures.15 With the use of these species
dependent traits, elements of a sample can be sequentially
removed from a matrix, or the matrix itself volatilized, and in-
line separated. Little is published concerning the reactive
chemistry of NF3. Mass spectrometry provides one method to
investigate potential metal−NF3 adduct formation, changes in
fluorination product, or product distribution relative to other
fluorinating reagents.
A quadrupole mass spectrometer (QMS) with an electron
ionization source (EI, formerly electron impact ionization) was
directly coupled to the gas outlet of a thermogravimetric
Received: February 11, 2015
© XXXX American Chemical Society
A
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approximately 0 °C reaction temperature, tellurium tetra-
fluoride (TeF4) is exclusively formed.17 The tetrafluoride is a
white crystalline solid at room temperature with a melting point
of 129 °C. At 195 °C, TeF4 disproportionates to form
elemental Te and TeF6.21 When tellurium metal is finely
powdered, fluorine reacts to form the hexafluoride even at
liquid nitrogen temperatures.22 Scheele et al. showed that NF3
begins to slowly fluorinate tellurium dioxide (TeO2) around
260 °C with increased fluorination at 360 °C.13 Though other
methods have been employed,23,24 no mass spectra of TeF6,
TeF4, or F5TeOTeF5 have been reported in the literature using
electron ionization mass spectrometry.
near 350 °C with production of the hexafluoride reaching 8
μmol/min at 500 °C. The yield of TeF6 produced was
controlled by the amount of starting tellurium used in the
experiment.
3.1. Raman Spectrum of TeF6. Raman spectroscopy was
performed to verify the product of the reaction of Te metal and
tellurium dioxide with NF3. When tellurium was reacted with
NF3 and the product was cryogenically condensed, a white solid
was observed in the quartz optical cell along with a separate,
unidentified red-violet solid. Upon removing the cryogenic bath
and allowing the cells to return to room temperature, both
solids were observed to sublime. The red-violet solid sublimed
rapidly following removal of the cryogen. The white solid was
observed to begin sublimation at approximately −35 °C. The
behavior of the white solid was consistent with physical changes
expected for TeF6.16 In addition, a separate white solid was
observed to condense (without the need of cryogen) in the arm
of the optical cell at the interchange between the TGA and
quartz apparatus. This solid dissipated when exposed to air.
Following exposure to air, the tube walls showed noticeable
etching. This solid is consistent with earlier reports of
dinitrosylhexafluorosilicate [(NO)2SiF6] production.32,33 De-
spite earlier reports,34−38 spectrum acquisition under these
conditions was found to be difficult, which is suspected to be
due to transient heating of the sample from the Raman laser
excitation source. Additional sources of difficulty were from the
use of NF3 rather than fluorine gas as the fluorinating agent,
and possibly from the use of a continuous flow system rather
than the typical condensation from a static system. The
coproduction of the red-violet and white solids was consistent
with early reports of pure NF3 fluorinations of tellurium in
quartz experimental apparatus at similar cryogenic temper-
atures.39−42
To examine the nature of the red-violet solid, control
experiments were also performed in which approximately 1000
Torr of NF3 was heated in a stainless steel vessel without the
presence of tellurium. When hot NF3 exiting the 500 °C reactor
was cooled directly into the Raman cell, a red-violet solid was
collected, confirming that this product does not require
tellurium to be produced, and is likely not part of the tellurium
reaction being considered. After several heating and cooling
cycles between −60 and −196 °C, which vaporized and
condensed the material, the red-violet solid could not be
recovered, and a viscous blue liquid condensed from the gas
phase near −60 °C (Figure 1). Over time, as the sample was
warmed to room temperature, a yellow-brown gas was observed
in the cell (observed in both setups) which was confirmed by
2. METHODS
Tellurium metal and tellurium dioxide were both used as starting
materials in this study and were available from house chemical stocks
at Pacific Northwest National Laboratory. The tellurium used in these
experiments came from commercial sources. The gases used
throughout the experiments were 99.995% purity NF3 purchased
from Air Liquide (Kennewick, WA) and 99.9995% argon purchased
from Oxarc (Pasco, WA). Volatile tellurium hexafluoride (TeF6) was
produced in a modified Seiko thermogravimetric analyzer (TGA)
model 5200 with 5% NF3 flow in argon at 50 mL/min total gas flow.
Modifications that provide some protection from corrosive reactions
on the interior of the TGA are described in earlier reports.12,13 The
TGA was ramped to 500 °C at 10 °C/min and held isothermally
through the completion of the reaction with results similar to those
previously reported.13
Mass spectra were collected by directly coupling the gas outlet of
the TGA to a molecular leak inlet valve of a quadrupole mass
spectrometer (QMS) (1.2 MHz, 19 mm rods, 500 amu range; Extrel
CMS, Pittsburgh, PA) with an EI source (tungsten filament). The
mass spectrometer was arranged to sample gas directly from the outgas
line of the TGA, through a heated line designed to prevent
condensation of the tellurium species. The gas sampler for the mass
spectrometer was arranged to introduce the sampled gas with
minimum travel distance to the electron impact ionization source.
Spectra were acquired in scanning profile mode at 250 amu/s and 19
microscans/acquisition. Reported spectra are the average of 101
consecutive acquisitions. A series of background spectra were taken
before the TGA temperature ramp was started and were used to
subtract the background from the TGA fluorination products’ spectra.
Raman analysis of the TGA products was performed separately by
cryogenically condensing (at −100 °C) the outgas products in a quartz
optical cell as the gas exited the TGA. The cell was composed of two 1
cm path length UV cuvettes isolable from each other by Teflon stop
cocks. Prior to experiments, argon gas was purged from the TGA
through the gas cell, through an empty trap (to halt potential
backflow), and then through a silicon oil bubbler to prevent air
inleakage. Condensed products were analyzed using an InPhotonics
RS2000, high resolution Raman spectrometer with a thermoelectrically
cooled charge-coupled detector (CCD) operating at −52 °C and a 670
nm, 150 mW diode laser as the excitation source. Laser power was
focused through an InPhotonics Raman fiber optic probe operated in a
180° back reflection mode.
Density functional theory (DFT) electronic structure calculations
were performed to elucidate the behavior of the ion fragments formed.
All calculations were performed with the NWChem 6.5 computational
chemistry program25 with the B3LYP exchange-correlation func-
tional26−29 and the Def2-TZVP basis and effective core potential for
tellurium30 and 6-311G++(3df, 3pd) basis for fluorine,31 respectively.
3. RESULTS AND DISCUSSION
Te metal and TeO2 were used to produce TeF6 by fluorination
with 5% NF3 in UHP argon in a TGA. Onset of TeF6
production (observed by mass loss in the TGA and detection
of product-related ions in the mass spectrometer) occurred
Figure 1. Nontellurium products cryogenically captured during NF3
treatment: (a) unidentified red-violet solid; (b) unidentified blue
liquid; (c) brown gas identified as NO2.
B
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Raman spectroscopy as a mixture of NO2 and N2O4.43 After
further repetitions of the heating and cooling cycles, the blue
liquid could no longer be recovered.
3.2. Mass Fragmentation of TeF6. Positive EI mass
spectra resulting from the fluorination of Te metal or TeO2
yielded similar results. Experiments showed that an electron
energy of 35 eV gave the best total ion intensity. The spectrum
resulting from the fluorination of Te metal is shown in Figure 3.
The production of NO2 and N2O4 suggests a series of
reactions from a reactive species that formed from hot NF3
which is consistent with formation of nitrosyl fluoride (NOF)
to produce nitrogenous oxides.32,44,45 Though unidentified, the
behaviors of the red-violet solid and blue liquid suggest that
these substances are related to this series of reactions. While the
initiating species was either too short-lived or unstable to be a
signature in the mass spectrum, the nitrogenous oxides all had
to be considered as well as the fragmentation pattern of NF3
itself in the assignment of background components. The mass
spectrum of NF3 and its EI fragmentation have been
discussed.46,47
Successful acquisition of the Raman spectrum of TeF6 solid
was accomplished by condensing the off-gas from the reaction
of approximately 160 mg of Te metal with NF3, which
produced sufficient material to avoid the previously described
difficulties. Further, the Raman spectrum was acquired
immediately to keep signal components of the side reactions
to a minimum. Attempts were also made to obtain the Raman
spectrum of the red-violet solid; however, the solid sublimed
too readily for our apparatus to resolve its spectrum.
Figure 3. Positive EI mass spectrum of TeF6 obtained through
reaction of tellurium metal with NF3. Spectrum obtained with an
electron energy of 35 eV.
After the material was warmed to room temperature, only a
white solid product could be obtained through use of cryogenic
solutions at −100 and −196 °C. Raman spectra were collected
and were consistent with spectra of tellurium hexafluoride
reported in the literature34−38 with major peaks observed at
698, 669, and 319 cm−1 as shown in Figure 2. Minor peaks at
+
The molecular TeF6+ ion was not observed. The ions Te+, Te2 ,
TeF+, TeF2 , TeF3 , TeF4 , and TeF5+ were all readily observed.
All eight of the natural tellurium isotopes were accounted for in
+
+
+
the Te+ and TeF5 series. The lowest abundance (0.09%) Te-
+
120 containing ions were not detected in the TeF+, TeF2 ,
+
+
+
TeF3 , and TeF4 series. Figure 4 shows the spectrum of the
resulting TeF5 series, and the resulting observed isotopic
+
abundances are reported in Table 1.
Figure 2. Observed Raman spectrum of solid TeF6 captured from
reacting NF3 with Te metal.
+
Figure 4. Positive EI mass spectrum of TeF5 resulting from the
ionization of TeF6 obtained through fluorination of tellurium metal
with NF3. Spectrum obtained with an electron energy of 35 eV.
280, 262, and 221 cm−1 are also observed. Following
sublimation of the tellurium hexafluoride, additional peaks are
observed which allowed identification of the 280 cm−1 peak as
N2O4.43 The other peaks remain unidentified, but are likely due
to contaminants from the additional NF3 reaction with the
quartz cell. At room temperature, no solid or liquid was
observed in the cell. The boiling points of TeF4 and
F5TeOTeF5 are above room temperature which suggests that
the only tellurium product present was the hexafluoride. The
use of both Te metal and TeO2 in these experiments indicates
that di- or trimeric fluorides or oxyfluorides of tellurium as
discussed in the literature20 were not produced under our
experimental conditions.
+
3.3. Source of Te+ and Te2 . An additional signal from m/
+
z 240 to 260 was also observed which was attributed to Te2
formation. Figure 5 shows a relative intensity spectrum of this
series, and calculated and measured abundances for each mass
can be seen in Table 2. The literature reports the synthesis of
only one tellurium dimer, Te2F10.17−19 Recent research suggests
that this compound was never synthesized and was actually
bis(pentafluorotelluryl) oxide (F5TeOTeF5).20 If the ditellu-
rium ions that were observed resulted from direct ionization
and fragmentation of F5TeOTeF5, an oxygen atom would be
C
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Consequently, these observations disfavor the argument for
formation of an oxyfluoro dimer by direct fluorination methods
under our experimental conditions.20
Table 1. Calculated and Observed Isotopic Abundance of
Natural Te Based on TeF5
+
abundance of
natural Te (%)
relative abundance of
natural Te (%)
measured relative
a
Tellurium metal (melting point = 450 °C) has been shown
to slowly volatilize and transfer down a tube within our
temperature range.48 As Te2 is the more stable state for
isotope
abundance (%)
130
128
126
125
124
123
122
120
34.1
31.8
18.8
7.1
100
93.1
55.3
20.7
13.9
2.6
100
92.5
55.1
20.9
14.0
2.6
tellurium in the gas phase,49,50 both Te+ and Te2 ions would
+
be observed in the mass spectrum if unfluorinated tellurium was
reaching the mass spectrometer. When tellurium metal was
heated in the absence of NF3, a mass loss was observed.
However, no tellurium mass signal was observed. Additionally,
4.7
0.9
2.6
7.5
7.6
+
when the ionization energy was lowered to 10 eV, TeFx ions
0.1
0.3
0.3
were no longer observed, while Te+ and Te2+ remained virtually
unchanged. This final observation suggests that the ditellurium
ions and the majority of the Te+ ions are not the direct result of
fragmentation from TeF6 ionization. Two hypotheses for this
set of signal observations are considered.
a
+
Calculated using TeF5 series from Te metal.
First, TeF6 could react with the internal parts of the transfer
system resulting in the decomposition to tellurium metal closer
to the mass spectrometer leak valve. This product could then
volatilize as Te2 and ionize in the mass spectrometer. After
tellurium was reacted in our experimentation and no further
signal was observed by mass spectrometry, the leak valve to the
mass spectrometer was closed, and the transfer line was flushed
with argon for several hours. The transfer line was then isolated
from further gas flow and coupled to a vessel containing
tellurium hexafluoride. When the leak valve to the mass
spectrometer was opened, Te+ and Te2 were immediately
+
observed. When the hexafluoride reached the mass spectrom-
+
Figure 5. Positive EI mass spectrum of Te2 resulting from the
ionization of TeF6 obtained through fluorination of tellurium metal
with NF3. Spectrum obtained with an electron energy of 35 eV.
+
eter, TeFx species were observed as well as a spike in the
amount of Te+ and Te2 . This suggests that TeF6 is reacting
+
with the stainless steel transfer line and decomposing to
tellurium metal. However, the vapor pressure of tellurium51
appears insufficient to completely account for the observed
signal of these two ions.
bridging the tellurium atoms and fragments with oxygen
incorporated would be observed elsewhere in the spectrum.
+
Table 2. Calculated and Observed Abundance of Te2 Masses from Pairing of Isotopes
a
mass
isotopic combination
130−130
calcd abundance (%)
relative calcd abundance (%)
measured relative abundance (%)
260
258
256
255
254
253
252
11.6
21.6
22.9
4.8
50.7
94.4
100
53.4
98.6
100
130−128
130−126
130−125
130−124
130−123
130−122
126−126
128−123
130−120
126−124
126−123
128−120
125−123
125−122
126−120
123−123
125−120
124−120
123−120
122−120
120−120
128−128
21.0
66.3
22.2
36.2
21.5
64.6
22.6
34.4
128−126
128−125
128−124
15.2
5.1
8.3
251
250
126−125
128−122
125−125
125−124
126−122
124−124
124−123
124−122
3.2
4.0
14.1
17.3
14.0
15.9
249
248
1.0
1.4
4.4
6.0
4.8
6.0
b
247
246
0.4
0.3
1.9
1.2
∼1.7
∼1.2
b
245
244
243
242
240
123−122
122−122
5.8 × 10−02
7.4 × 10−02
1.6 × 10−03
4.6 × 10−03
8.1 × 10−05
0.3
0.3
7.0 × 10−03
2.0 × 10−02
3.5 × 10−04
a
b
+
Calculated using Te2 series from Te metal. Estimated from spectra.
D
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show a decreasing trend from TeF+ to TeF5 indicating a
+
Second, a tungsten filament was used as the electron
ionization source in these experiments. This filament reaches
temperatures between 1600 and 2700 °C.52 At these temper-
atures, tellurium hexafluoride could thermally decompose53 to
+
stronger bond and greater stability, while the even series (TeF2
and TeF4 ) shows the opposite trend. The largest even species,
TeF6 , has five bond lengths comparable to the TeF5 bond
lengths with the exception of one long bond of 2.38 Å, and the
overall structure is a very strained octahedral. This suggests that
TeF6 will readily decompose to TeF5 and contribute to the
increased observed abundance of TeF5 . The bond length/
+
+
+
+
the metal and then ionize as Te+ and Te2 . We observed that
the Te+ and Te2+ ions appear and dissipate at the same rate as
the other TeFx+ ions in the mass spectrum. If the first pathway
(decomposition in the transfer line) was the primary pathway,
we’d expect different rates of in growth and the signal for these
ions to linger. This suggests that thermal decomposition is the
primary mechanism.
+
+
+
stability analyses also provide an explanation for the similar
abundances of the TeF+, TeF2 , and TeF3+ species, respectively.
+
+
With regard to Te2 , this ion is a doublet and analogous to the
O2 /O2 pair; the ion is more stable than Te2. All optimized
+
3.4. Relative Abundance of TeF6 Ion Fragments. Upon
further investigation of the signals presented in Figure 3, there
structures and coordinates are provided in the Supporting
Information.
is an alternating abundance of even (Te+, TeF2 , TeF4 , and
+
+
TeF6 ) and odd (TeF+, TeF3 , and TeF5 ) fluoride species. In
+
+
+
the odd series, ion formation favors species containing higher
4. CONCLUSIONS
numbers of fluorine atoms (TeF5 > TeF3 > TeF+).
+
+
Tellurium hexafluoride (TeF6) was formed by reacting Te
metal or TeO2 with NF3 at approximately 500 °C in a
thermogravimetric analyzer (TGA). The gas outlet of the TGA
was directly coupled to a quadrupole mass spectrometer
(QMS) with an electron ionization source. Formation of TeF6
was confirmed through separate analysis by cryogenic capture
of the tellurium fluorination product and analysis through
Raman spectroscopy.
Conversely, in the even series, the presence of fewer fluorine
atoms is favored for higher ion formation (Te+ > TeF2
>
+
+
+
TeF4 > TeF6 , not observed). The relative intensities of the
different observed species are shown in Table 3. Since the
Table 3. Relative Abundance of Observed Te Species
Collected from Approximately 25 fg/s TeF6
a
species
relative abundance (%)
When gaseous TeF6 is ionized with a 35 eV electron
ionization source, the reported mass spectrum was observed
Te+
76.8
which includes Te+, TeF+, TeF2 , TeF3 , TeF4 , and TeF5 . The
molecular ion was not observed. In addition, ditellurium ions
+
+
+
+
TeF+
14.5
+
TeF2
13.0
+
+
(Te2 ) were observed. We currently explain these ions along
TeF3
20.6
with the majority of the Te+ signal as due to thermal
decomposition of the TeF6 with the ionization source. An
+
TeF4
5.7
+
TeF5
100
alternating abundance of even (Te+, TeF2 , TeF4 , and TeF6 )
+
+
+
+
TeF6
Te2+
not observed
and odd (TeF+, TeF3 , and TeF5 ) fluoride species was also
observed. The odd fluorine ion species favored more fluorine
(TeF5+ > TeF3+ > TeF+) while the even ion species favored less
+
+
b
38.2
a
b
Calculated using 130Te species. Ratio of mass 256 to 130Te+.
fluorine (Te+ > TeF2+ > TeF4+ > TeF6 , not observed). We also
+
Raman data suggests that TeF6 is initially the major tellurium
reaction product, we believe that the absence of the observed
performed electronic structure calculations of the different
species to support our observations. The observed even/odd
stability pattern was explained by the Te−F bond lengths of
each species.
+
molecular ion (TeF6 ) is due to instability of the molecular ion.
DFT calculations were performed to test the hypothesis of
the stability of the ionic fragments. The results of the
calculations are summarized in Table 4. In a comparison of
the spin multiplicities of the odd species, the ground state of
ASSOCIATED CONTENT
■
+
TeF+ is a triplet (∼1.3 eV lower than the singlet), while TeF3
S
* Supporting Information
and TeF5+ are singlets. All species in the even series resulted in
Structures and Cartesian coordinates (in Å) of the various
species. The Supporting Information is available free of charge
doublet radical ions. The Te−F bond lengths for the odd series
+
Table 4. Calculated Energies (in Hartrees), Bond Lengths, Bond Angles, Coordinations, and Multiplicities of the Various TeFx
Species
energy
species
(Hartrees)
Te−F bond length (Å)
F−Te−F bond angle (deg)
coordination
linear
multiplicity
singlet
TeF+
(S)
TeF+
(T)
−367.589 39 1.857
−367.636 68 1.856
linear
triplet
+
TeF2
−467.535 14 1.847
−567.444 77 1.834
−667.232 95 1.898, 1.824
96.3
bent
doublet
singlet
+
TeF3
95.7
trigonal pyramid
+
TeF4
98.6, 96.0, 161.7
distorted
tetrahedron
doublet
+
TeF5
−767.101 87 ax 1.827, eq 1.819
90, 120, 180
trigonal
bipyramidal
singlet
+
TeF6
−866.875 29 1.810, 1.827, 1.831, 1.827,
88.5, 88.6, 96.1, 167.9, 152.2, 103.9, 88.6, 103.9, 88.5, 96.1, 83.9,
76.2, 76.0, 83.9, 180.0
very distorted
octahedral
doublet
1.831, 2.380
E
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AUTHOR INFORMATION
Corresponding Author
*E-mail: richard.clark@pnnl.gov.
Notes
■
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS
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This research was funded by Pacific Northwest National
Laboratory (PNNL) utilizing Laboratory Directed Research
and Development (LDRD) funds. Pacific Northwest National
Laboratory is operated by Battelle Memorial Institute for the
United States Department of Energy under DOE contract
number DE-AC05-76RL1830. This research was performed
under the Nuclear Forensics Postdoctoral Fellowship Program,
which is sponsored by the U.S. Department of Homeland
Security, Domestic Nuclear Detection Office, and the U.S.
Department of Defense, Defense Threat Reduction Agency. All
the calculations were performed using EMSL, a national
scientific user facility sponsored by the U.S. Department of
Energy’s Office of Biological and Environmental Research and
located at PNNL.
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DOI: 10.1021/acs.inorgchem.5b00342
Inorg. Chem. XXXX, XXX, XXX−XXX